<h2>DESCRIPTION</h2>

The module <em>t.vect.observe.strds</em> is used to observe specific
locations in a space time raster dataset over a period of time using
vector points.

The first input is a vector map layer with vector points. The second 
input is one or several space time raster datasets (STRDS) that should 
be sampled over time at the vector point positions. The space time 
raster dataset will be sampled over its whole temporal extent (from 
start to end). A column name must be specified for each input space
time raster dataset.
<p>
The result is a new space time vector dataset that contains a single
(new) vector map which links to as many time-stamped attribute tables
as raster map layers are present in the input space time raster dataset. 
Hence, for each time step in the space time raster dataset a new 
attribute table is created. The GRASS GIS Temporal Framework allows 
to time stamp attribute tables that can be linked to a single vector 
map layer.
<p>
The module <em>v.what.rast</em> is used internally for sampling the 
time stamped raster map layers. All sampled values of a single time 
stamped raster map layer are written into a new time stamped attribute 
table.
<p>
Use <em>t.vect.db.select</em> to print attribute values of the space
time vector dataset to stdout.

<h2>EXAMPLE</h2>

The example shows how to create a space time vector dataset and a vector
layer starting from a point vector and a space time raster dataset:

<div class="code"><pre>
t.vect.observe.strds input=precip_30ynormals_3d strds=tempmean_monthly \
                     output=precip_stations vect=precip_stations_monthly \
                     columns=month

t.info precip_stations type=stvds
 +-------------------- Space Time Vector Dataset -----------------------------+
 |                                                                            |
 +-------------------- Basic information -------------------------------------+
 | Id: ........................ precip_stations@climate_2009_2012
 | Name: ...................... precip_stations
 | Mapset: .................... climate_2009_2012
 | Creator: ................... lucadelu
 | Temporal type: ............. absolute
 | Creation time: ............. 2014-12-02 00:42:39.187615
 | Modification time:.......... 2014-12-02 00:42:55.215169
 | Semantic type:.............. mean
 +-------------------- Absolute time -----------------------------------------+
 | Start time:................. 2009-01-01 00:00:00
 | End time:................... 2013-01-01 00:00:00
 | Granularity:................ 1 month
 | Temporal type of maps:...... interval
 +-------------------- Spatial extent ----------------------------------------+
 | North:...................... 306221.830194
 | South:...................... 27606.895351
 | East:.. .................... 917004.829165
 | West:....................... 151768.568246
 | Top:........................ 1615.44
 | Bottom:..................... 2.4384
 +-------------------- Metadata information ----------------------------------+
 | Vector register table:...... vector_map_register_be074525097c4088997c9a1979f17065
 | Number of points ........... 6664
 | Number of lines ............ 0
 | Number of boundaries ....... 0
 | Number of centroids ........ 0
 | Number of faces ............ 0
 | Number of kernels .......... 0
 | Number of primitives ....... 6664
 | Number of nodes ............ 0
 | Number of areas ............ 0
 | Number of islands .......... 0
 | Number of holes ............ 0
 | Number of volumes .......... 0
 | Number of registered maps:.. 49
 |
 | Title:
 | Observaion of space time raster dataset(s) tempmean_monthly
 | Description:
 | Observation of space time raster dataset(s) tempmean_monthly with vector map precip_30ynormals_3d
 | Command history:
 | # 2014-12-02 00:42:39
 | t.vect.observe.strds input="precip_30ynormals_3d"
 |     strds="tempmean_monthly" output="precip_stations"
 |     vect="precip_stations_monthly" columns="month"
 |
 +----------------------------------------------------------------------------+


v.info precip_stations_monthly
 +----------------------------------------------------------------------------+
 | Name:            precip_stations_monthly                                   |
 | Mapset:          climate_2009_2012                                         |
 | Location:        nc_spm_temporal_workshop                                  |
 | Database:        /grassdata                                                |
 | Title:           North Carolina 30 year precipitation normals (3D)         |
 | Map scale:       1:1                                                       |
 | Name of creator: neteler                                                   |
 | Organization:                                                              |
 | Source date:     Wed May  9 14:32:39 2007                                  |
 | Timestamp (first layer): none                                              |
 |----------------------------------------------------------------------------|
 | Map format:      native                                                    |
 |----------------------------------------------------------------------------|
 |   Type of map: vector (level: 2)                                           |
 |                                                                            |
 |   Number of points:       136             Number of centroids:  0          |
 |   Number of lines:        0               Number of boundaries: 0          |
 |   Number of areas:        0               Number of islands:    0          |
 |   Number of faces:        0               Number of kernels:    0          |
 |   Number of volumes:      0               Number of holes:      0          |
 |                                                                            |
 |   Map is 3D:              Yes                                              |
 |   Number of dblinks:      49                                               |
 |                                                                            |
 |   Projection: Lambert Conformal Conic                                      |
 |                                                                            |
 |               N:     306221.830194    S:      27606.895351                 |
 |               E:     917004.829165    W:     151768.568246                 |
 |               B:            2.4384    T:           1615.44                 |
 |                                                                            |
 |   Digitization threshold: 0                                                |
 |   Comment:                                                                 |
 |                                                                            |
 +----------------------------------------------------------------------------+
</pre></div>

<h2>SEE ALSO</h2>

<em>
<a href="t.create.html">t.create</a>,
<a href="t.info.html">t.info</a>,
<a href="t.vect.db.select.html">t.vect.db.select</a>,
<a href="t.vect.what.strds.html">t.vect.what.strds</a>
</em>

<h2>AUTHOR</h2>

S&ouml;ren Gebbert, Th&uuml;nen Institute of Climate-Smart Agriculture

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